acme packet

Internet cafes often use DHCP services, such as the DCHP service provided by the diskless system server and the DCHP service of the router. First, the network administrator must understand the DHCP protocol packets, DHCP is a protocol designed by IETF to achieve automatic IP address configuration. The following types of DHCP packets are available. (1) DHCPDISCOVER (0 × 01), the first packet from the Client starting the DHCP process; (2) DHCPOFFER (0

Now we have to add port information to the UDP packet structure, which requires a new protocol. The simplest implementation is the UDP Protocol. Its format is almost in front of the data and the port number is added. A UDP packet is composed of two parts: "Header" and "data. The "Header" section mainly defines the sending and receiving ports, and the "data" section is the specific content. Then, put the ent

Introduction: The LLC sublayer read and forget, write in here convenient memory.Mac won't say it. LLC format Baidu.LLC Sub-layerThe LLC sublayer in the IEEE802.3 frame adds some other useful features in addition to defining traditional link-layer services. These features are provided by the DSAP, Ssap, and control fields.For example, the following three types of point-to-point transport services: Non-connected packet transport serviceThe curr

connection without packet loss. Then, I directly access and operate the sales system on the workstation in the Central Data Center. Everything is normal, it indicates that the network of the sales server and the central data center is normal. Is there a network problem at the sales office? Try to restart the switch at the sales office and test that the fault still exists.Are all computers in the sales office infected with viruses? I brought another l

This is a creation in Article, where the information may have evolved or changed. In the development of artificial customer service system with Golang encountered the problem of sticky bag, then what is sticky bag it? For example, we and the Client Convention data interaction format is a JSON-formatted string: {"Id": 1, "Name": "Golang", "message": "Message"} When the client sends the data to the server, if the server does not receive it in time, and the client sends a data, the server receives

I. Overview:After listening to the ASA video from yeslab's instructor QIN Ke, the FTP server is on the Outside and the FTP client is on the Inside. In this case, the active FTP server works normally because: ftp review can enable FTP to normally Modify FTP application layer data when traversing PAT), and enable FTP to actively initiate packets from Outside to Inside in active mode to pass the firewall smoothly. Because the configuration of PAT on the vro and FTP work normally, we plan to test wh

FFmpeg http://www.ffmpeg.club/Avpacket is ffmpeg used to store encoded video frame data, we analyze this structure, first put out the source code of Avpacket declaration in ffmpeg3.2:typedef struct AVPACKET {/*** A reference to the reference-counted buffer where the packet data is* stored.* could be NULL, Then the packet data isn't reference-counted.*/avbufferref *buf;/*** Presentation timestamp in avstream

First, let's look at the three-time handshake process for TCP1) First handshake: When establishing a connection, the client sends a SYN packet (SYN=J) to the server and enters the syn_sent state, waiting for the server to confirm; SYN: Synchronous sequence Number (Synchronize Sequence Numbers).2) Second handshake: The server receives the SYN packet, must confirm the customer's SYN (ACK=J+1), simultaneously

Qt packet abstraction based on TCP network program I have no experience before. When sending data packets, the packet header and other information are all implemented by redefining a struct. Different protocol packages have different structs. The result is as follows: how many upper-layer business protocol packages are there? I will re-define a new structure corresponding to the ending of the

Lab environment: System: centos6.2 linux2.6 VMware Virtual Environment Test Three machines are available: A, B, and C. A has a NIC: eth1: 1923168.66.225 B: One NIC: eth0: 192.168.66.10 C: One NIC: eth0: 192.168.66.11 For some reason, I want B to send data packets to C but not directly, and a can exchange data packets with B and C. At this time, I want, B sends the data packet to a, and then a forwards the data pa